NUMBERS & PLACE VALUES

Transcription

1 Page 1 of 28 MATH MILESTONE # 1 NUMBERS & PLACE VALUES The word, milestone, means a point at which a significant (important, of consequence) change occurs. A Math Milestone refers to a significant point in the understanding of mathematics. To reach this milestone one should be able to read and write numbers into the billions and more. The word, datum, means a single piece of information. Each datum given here is accompanied by a diagnostics, which helps locate any blanks in understanding. Datum 1.1 Mathematics starts with counting Mathematics is a learning tool, which teaches us how to think systematically A UNIT is what we count one at a time. A NUMBER is how many we have counted Abacus provides a systematic way of counting. Zero is an absence of count On abacus, counts of ten beads on a wire are regrouped as a count of one bead on the next wire Different DIGITS are a short hand for different number of beads on a wire Numbers beyond nine have a digit for TENS in addition to a digit for ONES Numbers beyond ninety-nine have an additional digit for HUNDREDS Digits are like letters. Numbers are like words. The place values of ONE, TEN and HUNDRED form a group The Group of THOUSANDS consists of ONE thousand, TEN thousands, and HUNDRED thousands The Group of MILLIONS consists of ONE million, TEN millions, and HUNDRED millions The Group of BILLIONS consists of ONE billion, TEN billions, and HUNDRED billions Diagnostic Test Summary Page Glossary... 27

2 Page 2 of 28 Get a simple ABACUS, as described in Lesson 1.4. Alternately, you may access the VIRTUAL ABACUS at for the purpose of this milestone. Please consult the Glossary supplied with this Milestone for mathematical terms. Consult a regular dictionary at for general English words that one does not understand fully. Do the Diagnostics in the sequence given. Then study the lessons, as necessary. Researched and written by Vinay Agarwala Edited by Ivan Doskocil

3 Page 3 of 28 MATH MILESTONE # 1 NUMBERS & PLACE VALUES J Datum 1.1: Mathematics starts with counting. Diagnostics 1. Count the fingers on your two hands. How many fingers are there? 2. How will you show the number SEVEN using your fingers? Lesson 1.1: Study the following as determined from Diagnostics.. 1. In counting, we call out the first item as ONE, the next item as TWO, the next item as THREE, and so on. NOTE: The counting numbers are also referred to as Natural Numbers. 2. The following finger configurations have been used to represent the counts from ONE to FIVE using one hand.

4 Page 4 of The following finger configurations have been used to represent the counts from SIX to TEN using both hands.

5 Page 5 of 28 J Datum 1.2: Mathematics is a learning tool, which teaches us how to think systematically. Diagnostics 1. How does counting show us what Mathematics is? 2. What can we learn from Mathematics? Lesson 1.2: Study the following as determined from Diagnostics. 1. When we count, we learn how many things are there. Thus, counting may be looked upon as a tool for learning. The word MATHEMATICS comes from a Greek word, mathema, which means, learning. Mathematics, essentially, is a tool for learning. 2. One counts in the sequence: ONE, TWO, THREE, FOUR, FIVE, etc. always. When one knows the system of counting one can easily tell the next number. This is systematic learning, which reduces the need to memorize. Mathematics teaches us to think systematically.

6 Page 6 of 28 J Datum 1.3: A UNIT is what we count one at a time. A NUMBER is how many we have counted. Diagnostics 1. What is the unit when you are counting pennies? 2. What is the unit when you are counting hundred-dollar bills? 3. Identify which of the following are numbers and which are units. (a) Dollar (b) Three (c) Cup (d) Group (e) Ten (f) Cat (g) Seven Lesson 1.3: Study the following as determined from Diagnostics. 1. A UNIT is what we count one at a time. (a) When we count fingers one at a time, each finger is a unit. (b) When we count chairs one at a time, each chair is a unit. (c) When we count ten-dollar bills one at a time, each ten-dollar bill is a unit. 2. A NUMBER is how many we have counted. (a) When we say, eight fingers, the number is EIGHT and the unit is A FINGER. (b) When we say, six chairs, the number is SIX and the unit is A CHAIR. (c) When we say, three ten-dollar bills, the number is THREE and the unit is a tendollar bill.

7 Page 7 of 28 J Datum 1.4: Abacus provides a systematic way of counting. Zero is an absence of count. Diagnostics 1. On an Abacus, point to the beads counted; point to the beads in storage. 2. Show the following counts on abacus. (a) Seven (b) four (c) Nine 3. What is zero? Show zero on abacus. Lesson 1.4: Study the following as determined from Diagnostics. 1. An ABACUS is a counting board with ten wires and ten beads on each wire. The word ABACUS comes from a word meaning, a board sprinkled with dust for writing. 2. We count by moving beads to the right one at a time as follows.

8 Page 8 of You may get a simple wooden abacus from a Toy Shop. Or, you may access the virtual abacus at 4. One counts on abacus by moving beads from left to right. The beads on the right show the count. The beads on the left are in storage. 5. When all the beads are on the left, and no beads on the right, there is no count. We may say that the count is ZERO. ZERO is absence of quantity.

9 Page 9 of 28 J Datum 1.5: On abacus, counts of ten beads on a wire are regrouped as a count of one bead on the next wire. Diagnostics 1. Show ten on abacus by counting on first wire. 2. Show ten on abacus after regrouping to next wire. 3. Count on abacus from eight to twelve demonstrating the rule of regrouping. Lesson 1.5: Study the following as determined from Diagnostics. 1. Counts of ten beads on a wire are regrouped as count of one bead on the next wire. Therefore, we show TEN on abacus not with ten beads on the first wire, but with one bead on the second wire. This is like regrouping 10 pennies into a dime. 2. Therefore, we count from nine to eleven as follows.

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11 Page 11 of 28 J Datum 1.6: Different DIGITS are short hand for different number of beads on a wire. Diagnostics 1. What is the idea behind DIGITS? 2. How many different digits are there? 3. How many digits does it take to write the number ten? Lesson 1.6: Study the following as determined from Diagnostics. 1. Digits provide shorthand on paper for how many beads are counted on a wire of abacus. The digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 as follows. 2. There is no new digit needed for TEN because it can be written with existing digits after the Rule of Regrouping is applied. TEN is written with two digits as 10.

12 Page 12 of 28 J Datum 1.7: Numbers beyond nine have a digit for TENS in addition to a digit for ONES. Diagnostics 1. The number sixteen is made up of TEN and ONES. 2. The number seventy-five is made up of TENS and ONES. 3. Show the following counts on abacus. Write them down using digits. (a) Thirteen (b) Seventeen (c) Twenty (d) Fifty (e) Thirty-seven (f) Eighty (g) Seventy-three (h) Ninety-seven 4. Read the following numbers: (a) 12 (b) 15 (c) 19 (d) 55 (e) 83 (f) 70 (g) 49 (h) 94 Lesson 1.7: Study the following as determined from Diagnostics. 1. The next count after ten is ten and one, or ELEVEN. This will be one bead on the second wire (TENS), and one bead on the first wire (ONES). For subsequent counts add beads on the first wire. The counts after ten are: FOURTEEN FIFTEEN SIXTEEN... 16

13 Page 13 of 28 SEVENTEEN EIGHTEEN NINETEEN At count TWENTY; once again we regroup the ten ONES on the first wire, as one TEN on the second wire. TWENTY is, therefore, written as Each bead on the second wire is a TEN. We count on the second wire by TENS as, Ten, twenty, thirty, forty fifty, sixty, seventy, eighty, and ninety FORTY FIFTY SIXTY SEVENTY EIGHTY NINETY Please note that each bead on the first wire is a ONE; and we count the ONES as, One, two, three, four, five, six, seven, eight, and nine

14 Page 14 of Thus, we may show numbers as a combination of TENS and ONES. (a) The number THIRTY-FOUR is made up of 3 TENS and 4 ONES. (b) The number FIFTY-EIGHT is made up of 5 TENS and 8 ONES. (c) The number NINETY-NINE is made up of 9 TENS and 9 ONES.

15 Page 15 of 28 J Datum 1.8: Numbers beyond ninety-nine have an additional digit for HUNDREDS. Diagnostics 1. Three hundred seven is made up of HUNDREDS, TENS and ONES. 2. Show the following counts on abacus, and then write them down using digits. (a) Three hundred twelve (d) Five hundred eighty (b) Three hundred twenty-one (e) Five hundred eight (c) Three hundred five (f) Nine hundred 3. Read the following numbers: (a) 111 (b) 277 (c) 658 (d) 704 (e) 410 Lesson 1.8: Study the following as determined from Diagnostics. 1. One more count from NINETY-NINE gives us all the ten beads to the right on the first wire. 2. We apply the Rule of Regrouping and regroup them as one bead on the next wire. This gives us all the ten beads to the right on the second wire. 3. We apply the Rule of regrouping again and regroup them as one bead on the next wire. This gives us one bead to the right on the third wire. This we call one hundred.

16 Page 16 of Each bead on the third wire is a HUNDRED. We count on the third wire by HUNDREDS as, One hundred, two hundreds, three hundreds, four hundreds, five hundreds, and so on 5. Thus, we may show numbers as a combination of HUNDREDS, TENS and ONES. (a) The number Two Hundred Seventy-Five is made up of 2 HUNDREDS, 7 TENS and 5 ONES. (b) The number Three Hundred Eighty-Seven is made up of 3 HUNDREDS, 8 TENS and 7 ONES. (c) The number Six Hundred Five is made up of 6 HUNDREDS, 0 TENS and 5 ONES.

17 Page 17 of 28 J Datum 1.9: Digits are like letters. Numbers are like words. The place values of ONE, TEN and HUNDRED form a group. Diagnostics 1. What is the difference between a digit and a number? 2. How many different digits are there in our numbering system? 3. Is 7 a digit or a number? 4. How many single-digit numbers are there? 5. How many double-digit numbers are there? 6. What are the smallest and largest three-digit numbers? Lesson 1.9: Study the following as determined from Diagnostics. 1. Digits are used to write numbers, just like letters are used to write words. The number three hundred ninety-five is written with three digits: 3, 9, and 5. 5 is a number written with one digit, just like I is a word written with one letter. 35 is a number written with two digits, just like ME is a word written with two letters. 164 is a number written with three digits, just like YOU is a word written with three letters. From 0 to 9 we have single-digit numbers. There are nine single-digit numbers and zero. From 10 to 99 we have double-digit numbers. There are ninety double-digit numbers. From 100 to 999 we have 3-digit numbers. There are nine hundred 3-digit numbers. 2. The digits in a number has have place values of ONE, TEN and HUNDRED from right to left. The number three hundred ninety-five is made up 5 ONES, 9 TENS, and 3 HUNDREDS. These place values form a basic group of three.

18 Page 18 of The place values of ONE, TEN, and HUNDRED correspond to the first, second, and third wires of the abacus. Note that the same three colors may be used consistently for ONES, TENS, and HUNDREDS, in this and subsequent groups. 4. From one place value to the next, the value increases by a factor of TEN.

19 Page 19 of 28 J Datum 1.10: The Group of Thousands consists of ONE thousand, TEN thousands, and HUNDRED thousands. We will call Group of Thousands just THOUSANDS. Diagnostics 1. Place a comma to separate thousands from the basic group. (a) 3829 (b) (c) (d) (e) Read the following numbers. (a) 1,111 (c) 532,658 (e) 300,005 (b) 23,277 (d) 500,074 (f) 101, Write the following numbers using digits. (a) Six thousand, three hundred sixty-five (b) Ninety Eight thousand, eight hundred one (c) Two hundred sixty thousand, four hundred twenty seven (d) Nine hundred thousand, ninety-nine (e) Three hundred twenty-nine thousand, five hundred forty-two (f) Seventy-seven thousand, six hundred (g) Four hundred thousand, five (h) Two hundred thirteen thousand, eighty-six (i) Six hundred six thousand, sixty-six Lesson 1.10: Study the following as determined from Diagnostics. 1. The Rule of Regrouping applies to digits beyond the THOUSANDS as follows. 10 HUNDREDS may be exchanged for 1 THOUSAND on fourth wire. 10 THOUSANDS may be exchanged for 1 TEN THOUSAND on fifth wire. 10 TEN THOUSANDS may be exchanged for 1 HUNDRED THOUSAND on sixth wire.

20 Page 20 of Thus, the THOUSANDS is a group of ONE, TEN, and HUNDRED. A comma is used to separate the thousands group from the basic group. For example, the following number is made up of We read this number as: Eight hundred twenty-six thousand, five hundred ninetythree. 3. When no count exists for a place value, a zero is placed there. For example, in the following number the place value of HUNDRED is missing. This number is written as shown below. We read this number as: Six hundred eighty-three thousand, fifty-three,

21 Page 21 of 28 J Datum 1.11: The Group of Millions consists of ONE million, TEN millions, and HUNDRED millions. We will call Group of Millions just MILLIONS. Diagnostics 1. Place commas at the correct place in the following numbers (a) (c) (e) (b) (d) Read the following numbers. (a) 5,762,869 (c) 765,532,658 (e) 9,009,009 (b) 27,045,008 (d) 300,006,074 (f) 590,008, Write the following numbers. (a) Two million, three hundred four thousand, five hundred sixteen (b) Forty-five million, four hundred sixty-four thousand, eight hundred one (c) Two hundred sixty million, thirty-six thousand, four hundred twenty seven (d) Eight million, seven thousand, ninety-nine (e) Six hundred forty-three million, eighty-six (f) Sixty-four million, two hundred six thousand (g) One hundred eleven million, two hundred fifty- four thousand, five (h) Nineteen million, nine hundred thousand, nineteen (i) One hundred sixty million, six Lesson 1.11: Study the following as determined from Diagnostics. 1. The Rule of Regrouping applies to digits beyond the THOUSANDS as follows. 10 HUNDRED THOUSAND may be exchanged for 1 MILLION on seventh wire. 10 MILLIONS may be exchanged for 1 TEN MILLION on eighth wire. 10 TEN MILLIONS may be exchanged for 1 HUNDRED MILLION on ninth wire.

22 Page 22 of Thus, the MILLIONS is a group of ONE, TEN, and HUNDRED. A comma is used to separate the millions group from the thousands group. For example, the following number is made up of We read this number as: Seven hundred fourteen million, eight hundred twenty-six thousand, five hundred ninety-three. 3. The following number is made up of 600 MILLIONS, 83 THOUSANDS, and 3. When no count exists for a place value, a zero is placed there. We read this number as: six hundred million, eighty-three thousand, three.

23 Page 23 of 28 J Datum 1.12: The Group of Billions consists of ONE billion, TEN billions, and HUNDRED billions. We will call Group of Billions just BILLIONS. Diagnostics 1. Place commas at the correct place in the following numbers (a) (c) (e) (b) (d) Read the following numbers. (a) 1,002,002,009 (c) 249,765,532,658 (e) 9,009,009,009 (b) 38,027,045,008 (d) 302,241,006,074 (f) 300,590,008, Write the following numbers. (a) 6 billion, 425 million, 606 thousand, three hundred four (b) 25 billion, 43 million, 60 thousand, fifty (c) 793 billion, 446 million, 237 thousand, five hundred sixty-five (d) 100 billion, 3 million, 2 thousand, one (e) 27 billion, 67 million, 35 thousand, eighty-seven (f) One billion, five million, six (g) Ten billion, one hundred million, fifty-five thousand, twelve (h) Six hundred six billion, three hundred forty-one (i) Three hundred billion, forty million, thirty-four Lesson 1.12: Study the following as determined from Diagnostics. 1. The Rule of Regrouping applies to digits beyond the MILLIONS as follows. 10 HUNDRED MILLIONS may be exchanged for 1 BILLION on the tenth wire. 10 BILLIONS may be exchanged for 1 TEN BILLION. 10 TEN BILLIONS may be exchanged for 1 HUNDRED BILLION. Note that, on abacus, three colors may be used consistently for ONES, TENS, and HUNDREDS, in all groups.

24 Page 24 of This number above is made up of 3 BILLIONS, 714 MILLIONS, 826 THOUSANDS, and 593. It is read as three billion, seven hundred fourteen million, eight hundred twenty-six thousand, five hundred ninety-three. Thus, the BILLIONS is a group of ONE, TEN, and HUNDRED. A comma is used to separate the billions group from the millions group. For example, the following number 3. The number below is made up of 132 BILLIONS, 603 MILLIONS, 41 THOUSANDS, and 299. It is read as one hundred thirty-two billion, six hundred three million, forty-one thousand, two hundred ninety-nine. Note that no place value is skipped. Since there are no counts for ten million, and hundred thousand, zeros are placed there as a place-holder. 4. Beyond BILLIONS we have groups of TRILLIONS QUADRILLION QUINTILLION SEXTILLION SEPTILLION OCTILLION NONILLION DECILLION, etc.

25 Page 25 of 28 DIAGNOSTIC TEST Before you proceed to Milestone #2, go through the following diagnostic test to find out if you understand the material of Milestone #1 fully. 1. Read the following numbers. (Lessons 1.9 to 1.12) (a) 25,807 (d) 3,000,009,133 (b) 357,000 (e) 325,601,213,000,102 (c) 3,007, Write the following numbers. (Lessons 1.9 to 1.12) (a) Seventy-seven thousand, three hundred nine (b) Forty-two thousand, seven (c) Six million, sixty-six thousand, sixty (d) Four hundred forty-four thousand, four (e) One hundred eight billion, four hundred fifty-six million, eighty-seven 3. Which of the following are units, and which are numbers? (Lesson 1.3) (a) Dollar (b) Ten (c) Ten-dollar bill (d) Group (e) Six (f) Cat (g) One 4. Which of the following are natural numbers? (Lesson 1.1) (a) 5 (b) ½ (c) 17 (d) 6 (e) 0 (f) 8 (g) ¼ 5. Is 10 a digit or a number? (Lesson 1.9) 6. Is 5 a digit or a number? (Lesson 1.9) 7. What are the place values of the underlined digits in the following numbers. (Lessons 1.9 to 1.12) (a) 10 (b) 145 (c) 3,257 (d) 5,000,400 (e) 31,952,833 If you failed to answer any question correctly, go back and restudy the corresponding lesson(s) marked at the question.

26 Page 26 of 28 SUMMARY The purpose of Mathematics is help one learn to think and reason in a systematic manner. This starts with learning to think systematically with numbers. The first part of Mathematics is called Arithmetic. The word ARITHMETIC (arithmos number + techne skill) means, Skill with numbers. Arithmetic helps us determine how many or how much of something. Therefore, it introduces the ideas of unit, number and place values. The first action of Arithmetic is counting. Arithmetic builds upon the concept of place values to develop a number logic that helps solve problems mentally. The logic of place values is expressed in the Rule of Regrouping as follows. WHENEVER ALL THE BEADS ARE TO THE RIGHT ON A WIRE, THEY ARE RETURNED TO THE LEFT AND REPLACED BY ONE BEAD TO THE RIGHT ON THE NEXT WIRE. The place value system makes it possible to write large numbers in shorthand. It also simplifies computation. This was a great advance over the Roman numerals used earlier. The place values in numbers are as follows. Note the repeating pattern of one, ten, hundred above. The first group of one, ten, hundred is the Basic Group. Next, we have the group of Thousands. Beyond that we have groups of Millions, Billions, Trillions, Quadrillion, Quintillion, Sextillion, Septillion, Octillion, Nonillion, Decillion, etc. To develop skill with numbers one may use fingers at first, and then move to the next step of abacus. The use of abacus helps one visually see the system of place values. The next level is mental math where one learns to think systematically with numbers, assisted by paper and pencil, and calculators. We feel strongly that student should first learn to do mental math before using calculator as an aid. Sole dependence on calculators and flash cards would prevent the student from developing the ability to think systematically. With the ability to think with numbers hampered, the student would not be able to learn math beyond the elementary level. Today, we take this system for granted, but the brilliance of the concepts of zero, the digits, the Rule of Regrouping, and the place values is simply astounding when fully understood.

27 Page 27 of 28 GLOSSARY Abacus Arithmetic Basic group Billions An abacus is a counting board with ten wires and ten beads on each wire. The word ABACUS comes from a word meaning, a board sprinkled with dust for writing. One can count up to billions on abacus. Arithmetic is the first aspect of Mathematics. The word ARITHMETIC comes from arithmos number + techne skill. Arithmetic literally means, Skill with numbers. It provides the skill needed to study quantity (not quality) of things. This refers to the basic group of place values: ONE, TEN, and HUNDRED. The basic group is followed by groups of thousand, Million, Billion, Trillion, Quadrillion, Quintillion, Sextillion, Septillion, Octillion, Nonillion, Decillion, etc. Each of these groups is made up of ONE, TEN, and HUNDRED. This refers to the place values in the Billion group: ONE BILLION, TEN BILLION, and HUNDRED BILLION. Carry-over Whenever a count reaches 10 on a wire of an abacus, it is carried over as 1 on the next wire. Similarly, when adding numbers by columns, the ten of the sum in a column is carried over to the column on the left. See the RULE OF ABACUS. Counting Datum Diagnostic test Digits Expanded notation Mathematics Mental math Milestone The purpose of counting is to find out how many things are there. One counts by sequentially calling out for each item, one, two, three, four, five, and so on. Datum is a single piece of information. Diagnostic Test is a test to diagnose or analyze the understanding of the student. The digits are symbols that we use to write numbers, much like letters are used to write words. For example, the number 386 is written with digits 3, 8, and 6. There are ten different digits 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. These ten digits may be used to write all possible numbers. This is a notation in which a number is expressed in terms of its place values. See Lesson A1.13. The word MATHEMATICS comes from a Greek word, mathema, which means, Things learned. Thus, mathematics consists of tools for learning. The purpose of Mathematics is to help develop the ability to think in a systematic manner. ABBREVIATION: Math or Maths. This is the third among the following gradients applied to the learning of arithmetic. (a) Counting on fingers (b) Counting on abacus (c) Mental math (d) Math with paper and pencil (e) Math with calculators. A milestone is a turning point. A Math Milestone refers to a turning point in the understanding of mathematics.

28 Page 28 of 28 Millions Natural numbers Number Number base Place value Quantity Regrouping, Rule of Systematic thinking Thousands Unit Zero This refers to the place values in the Million group: ONE MILLION, TEN MILLION, and HUNDRED MILLION. The counting numbers are also referred to as Natural numbers. Zero is not a natural number because it is not used in counting. A number is a way of telling how many units there are. In counting, each count is given a different NUMBER, such as, one, two, three, and so on. This is the base of the number because it determines how the number is to be constructed. It is the count at which regrouping occurs at any place in the number. Therefore, the largest digit used in the number is one less than this count. Place Value is the value a digit gets from its place in a numeral. The place values in a numeral from right to left are: ONE, TEN, HUNDRED, THOUSAND, TEN THOUSAND, and so on. A quantity refers to how many or how much of something, as opposed to the description of that thing. A quantity describes the number of units. The Rule of Regrouping is, When all beads are counted to the right on a wire, they are replaced by counting one bead to the right on the next wire. This means, 10 ONES are equal to 1 TEN, 10 TENS are equal to 1 HUNDRED, 10 HUNDREDS are equal to 1 THOUSAND, and so on. This rule underlies the idea of carry-over. When one gains familiarity with the fundamental ideas, which make up the subject of mathematics and thinks with them, then one can solve mathematical problems easily without resorting to memory. This is systematic thinking. Similar thinking may be developed for systems other than mathematics. This refers to the place values in the Thousand group: ONE THOUSAND, TEN THOUSAND, and HUNDRED THOUSAND. The word UNIT means one. A unit is what we count one at a time to see "how many" or how much" is there. When we count one penny at a time then each penny is a unit. When we count ten pennies at a time then each pile of ten pennies is a unit. When there is no quantity, we call it zero. Zero is a placeholder for absence of quantity.